Allergic asthma or extrinsic asthma is the most common form of asthma. Of the 20 million Americans with asthma, more than 7 million adults and 3 million children suffer from allergic asthma.
Allergic asthma results from an allergic reaction. Your immune system normally exists to fight off infection. In allergic asthma, however, your body senses allergens, which would normally be harmless, as foreign and mounts an attack against them. This immune attack can lead to asthma symptoms.
Allergic Asthma Symptoms
Many of the symptoms of allergic asthma and non-allergic asthma are the same and include:
Allergic asthma symptoms can be triggered by:
In general, allergic asthma is triggered when you inhale one of the previously mentioned triggers. Once you inhale these triggers, a complex reaction, referred to as the pathophysiology of asthma, begins, resulting in the development of asthma symptoms. Much of this results from the development of IgE.
Normally your immune system protects you from infections, but it can also be responsible for your worsening symptoms in allergic asthma. You may notice that at the same time you have allergy symptoms such as runny nose, watery eyes and other sinus complaints, your peak flows are lower, you are wheezing more, and you may experience more shortness of breath. So how are my immune system and allergic asthma linked?
If you have allergic asthma then you are most likely atopic, and have an inherited a predisposition towards allergy. As a result, your immune system develops an exaggerated response to the previously mentioned allergens or triggers. Your body senses these allergens, perceives them as foreign, and prepares to fight off them off as a foreign invader. This process, often referred to as the allergic cascade, occurs in 3 steps:
- Sensitization- First exposure to an allergen causing development of IgE.
- Early phase response- Upon re-exposure to an allergen, IgE now attacks or binds to the allergen, which causes the release of other chemicals, called mediators, that causes acute inflammation and bronchoconstriction.
- Late Phase response- Release of eosinophils after binding of allergen and IgE causes more inflammation and symptoms several hours after the exposure.
To summarize: your body is exposed to an allergen, which causes your body to develop IgE. On re-exposure to that allergen, IgE leads to the development of asthma symptoms.
Treating Allergic Asthma
Allergic asthma treatment primarily involves three main components:
- Monitoring of peak expiratory flow and asthma symptoms
- Avoidance of your allergic asthma triggers
- Treatment with medications
Environmental Control & Allergic Asthma
You can go a long way to reducing your exposure to allergic asthma triggers by:
American Academy of Allergy Asthma & Immunology. Accessed December 28, 2010. Is your asthma allergic?
National Heart, Lung, and Blood Institute. Accessed: January 7, 2011. Expert Panel Report 3 (EPR3): Guidelines for the Diagnosis and Management of Asthma